Positive crystals


  • Webster's Revised Unabridged Dictionary
    • Positive crystals (Opt) a doubly refracting crystal in which the index of refraction for the extraordinary ray is greater than for the ordinary ray, and the former is refracted nearer to the axis than the latter, as quartz and ice; -- opposed to negative crystal, or one in which this characteristic is reversed, as Iceland spar, tourmaline, etc.
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In literature:

Balzac's clericalism and royalism, which ultimately became so crystallized, were at this date in a position of unstable equilibrium.
"Balzac" by Frederick Lawton
The bands or rays observed through the same crystal have, in the spectrum, fixed positions, their intensity alone varying.
"Scientific American Supplement, No. 586, March 26, 1887" by Various
When the crystal faded, it was put into its box in the proper position and the electric light turned on.
"Tales of Space and Time" by Herbert George Wells
The tendency for crystals of lead to "tree" over from the negative to the positive plates is well known.
"The Automobile Storage Battery" by O. A. Witte
With stately tread he retired to a position behind the crystal globe.
"The Cry at Midnight" by Mildred A. Wirt
The difference in form of the ray-surface for positive and negative crystals is shown in figs.
"Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7" by Various
Engine-turned pickles, submerged in carbolic acid and frosted with vitriol crystals; positively antiscorbutic.
"The Army Mule and Other War Sketches" by Henry A. Castle
Occultists, as will readily be understood, set great store by crystal-gazing, finding in it positive proof of spirit action.
"Adventurings in the Psychical" by H. Addington Bruce

In news:

Three days before the public announcement that Georgie Perkins won a Crystal Apple Educator Award for her work as an instructional assistant at Peabody Charter School, she was notified that her position had been cut.
When the head changes position , these crystals shift.

In science:

V γ ’s, following (multiple) Compton scattering, was measured by triggering with a 4 ” Na(Tl) crystal on the second 511 keV emitted in the op posite direction, and on the 1275 keV γ .
Search for WIMPs in liquid argon
In the cases of U = 9 and 10, Econd was found to have finite positive bulk-limit values and sharply increase with increasing U, as expected. The Econd of the experimental size is obtained with U ~ 9. This illustrates that U depends on the crystal structure.
Superconducting Condensation Energy of the Two-Dimensional Hubbard Model in the Large-Negative-t' Region
Finally, for sufficiently large positive values of crystal field, magnetization curves always saturate at m = 1 and the system always undergoes a second order phase transition from a ferromagnetic phase to a paramagnetic phase with increasing temperature, which can be seen in Fig. (2f ) with D/J = 10.0.
Critical behavior and phase diagrams of a spin-1 Blume-Capel model with random crystal field interactions: An effective field theory analysis
From Fig. (5a), we see that as △/J increases then the tricritical point and first order transitions disappear, and the first order reentrance turns into double reentrance with three transition temperatures of second order, and phase transition lines shift to positive crystal field direction without changing their shapes.
Critical behavior and phase diagrams of a spin-1 Blume-Capel model with random crystal field interactions: An effective field theory analysis
The representation of position operator in terms of the Bloch states of a crystal is intimately related to the BC, and it thus appeared in the works of Adams and Blount on the topic much earlier than the rigorous formulation by Berry .
Optical injection and terahertz detection of the macroscopic Berry curvature